The present invention relates to stacking containers in which like containers may be stacked one on top of the other at different levels. The capability of stacking the containers at different levels relative to each other is to minimize the space required to hold a group of the containers when the containers are emptied or when products of different height are carried in the containers.
For example, a bakery may wish to transport large numbers of baked goods within a truck or trailer whose cargo space has a height of nine feet. Where the containers are loaded with loaves of bread, the containers must be stacked at levels relative to each other so that the bread is not crushed by the bottom of the next uppermost container. However, other products may be of a height less than that of a loaf of bread and containers of such other products, if stacked in the same vertical relationship as when the containers carried bread, would result in a substantial wastage of cargo space. For this reason, the prior art has produced containers of the type in which the present invention is concerned which are so-called three-level containers.
These three-level containers are so constructed that the containers, when empty, can be nested in a fully nested position in which a stack of containers will be of a minimum height. This is one level of the so-called three-level container. Various arrangements are provided so that the containers may be stacked in partially nested relationship at an intermediate level and at a higher upper level relative to each other. Examples of such prior art containers are found in U.S. Pat. No. 3,951,265 and in a commonly owned co-pending application Ser. No. 103,205 of Edwin L. Stahl et al, filed Dec. 13, 1979.
The present invention is especially directed to improvements on the container disclosed in the aforementioned application Ser. No. 103,205, by means of which four-level stacking can be achieved.